Which condition is listed as a differential diagnosis for Schizoid Personality Disorder?

• A. Autism Spectrum Disorder
• B. Histrionic Personality Disorder
• C. Personality Change Due to Another Medical Condition
• D. Substance Use Disorders

Answer: (C)

When evaluating schizoid personality disorder, it’s essential to consider conditions that could produce a similar pattern of social withdrawal and blunted affect, including changes driven by medical illness. The best differential here is personality change due to another medical condition, because medical or neurological problems can lead to a clear shift in personality and social behavior that might resemble a schizoid pattern. Before diagnosing a primary schizoid personality disorder, clinicians must rule out that an underlying medical condition is driving the presentation.

Other options describe different primary disorders with distinct features. For example, a pattern of dramatic, attention-seeking behavior points away from schizoid toward histrionic traits; substance use can cause mood or cognitive changes but doesn’t specifically mimic a long-standing schizoid style of detachment; autism spectrum disorder involves developmental history with early social-communication deficits and restricted interests, which helps differentiate it from a lifelong detachment not tied to developmental timing.